axaptapedia: CalendarWeek

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Источник: http://www.axaptapedia.com/CalendarWeek
==============

Summary: Calculate the correct Calendar Week according to the German Standard


///
/// Calculates the Calendar Week of a Date according to the German Standard
///
/// The Date
/// Returns an Integer representing the Calendar Week
///
///
/// This Method is only relevant for the German Culture.
/// It is considerably faster than the Method
/// .
///
///
/// The Calculation is based on the
/// C++-Algorithm from Ekkehard Hess out of an Article on
/// 29 July 1999 in the Newsgroup
/// borland.public.cppbuilder.language
///(released for general use)
///
///

static int calendarWeek_DE(Date inputDate)
{
real a = trunc((14 - (mthOfYr(inputDate))) / 12);
real y = year(inputDate) + 4800 - a;
real m = (mthOfYr(inputDate)) + (12 * a) - 3;
real jd;
real d4;
real L;
real dl;
int calendarWeek;
;

jd = str2int(substr(date2str(inputDate, 123, 2, 2, 2, 2, 2), 1, 2)) +
trunc(((153 * m) + 2) / 5) + (365 * y) +
trunc(y / 4) - trunc(y / 100) + trunc (y / 400) - 32045;
d4 = (jd + 31741 - (jd mod 7)) mod 146097 mod 36524 mod 1461;
L = trunc(d4 / 1460);
dl = ((d4 - L) mod 365) + L;

calendarWeek = trunc(dl / 7) + 1;

return calendarWeek;
}



Источник: http://www.axaptapedia.com/CalendarWeek